Drive control apparatus and control method for hybrid vehicles and hybrid vehicle

Abstract

A drive control apparatus for hybrid vehicles adapted to facilitate controlling a rotation speed of an internal combustion engine, preventing excess speeds of a motor generator. The drive control apparatus for hybrid vehicles is adapted for a drive control of a vehicle using outputs from an engine and motor generators, and includes a target engine operating point setter for setting up a target engine operating point to determine target engine torque and a target engine rotation speed of the engine from target engine power and an efficiency of system. A motor torque command value calculator sets up respective torque command values of the motor generators, and an engine torque corrector corrects the target engine torque by a target engine torque correction value set up based on the torque command values of the motor generators and permissible output torque of the motor generators.

The invention claimed is: 
     
       1. A drive control apparatus for a hybrid vehicle using outputs from an internal combustion engine and a motor generator, the drive control apparatus comprising:
 a target engine torque setter configured to set a target engine torque of the internal combustion engine; 
 a motor torque command value calculator configured to set a torque command value of the motor generator; and 
 an engine torque corrector configured to make a correction of the target engine torque by a target engine torque correction value which is set based on a permissible output torque of the motor generator and the torque command value of the motor generator, 
 wherein the engine torque corrector is configured to compare the torque command value of the motor generator to the permissible output torque of the motor generator and make the correction by decreasing the target engine torque when an absolute value of the permissible output torque of the motor generator is smaller than an absolute value of the torque command value of the motor generator. 
 
     
     
       2. The drive control apparatus according to  claim 1 , wherein the engine torque corrector includes:
 a permissible output torque calculator configured to calculate the permissible output torque of the motor generator based on a revolution of the motor generator; 
 a difference torque calculator configured to calculate a difference torque between the permissible output torque of the motor generator and the torque command value of the motor generator; 
 an engine torque correction component calculator configured to make a conversion of the difference torque to calculate an engine torque correction component; 
 a resultant torque calculator configured to make an addition between the target engine torque and the engine torque correction component to calculate a resultant torque; and 
 a target engine torque correction value setter configured to set the target engine torque correction value based on the resultant torque. 
 
     
     
       3. The drive control apparatus according to  claim 2 , wherein the engine torque corrector is configured to set a minimum engine torque to the target engine torque, and take a larger one of the minimum engine torque and the resultant torque after a comparison between the minimum engine torque and the resultant torque to set as the target engine torque correction value. 
     
     
       4. The drive control apparatus according to  claim 1 ,
 wherein the motor generator is a first motor generator; 
 wherein the drive control apparatus further comprises a second motor generator and a planetary gear set, the planetary gear set having four elements which are connected to the first motor generator, the internal combustion engine, an output section, and the second motor generator in this order on a collinear diagram; and 
 wherein the permissible output torque of the motor generator is a permissible output torque of the first motor generator and the torque command value of the motor generator is a torque command value of the first motor generator. 
 
     
     
       5. The drive control apparatus according to  claim 1 , further comprising a target engine operating point setter including the target engine torque setter, the target engine operating point setter being configured to set a target engine operating point to determine a target engine rotation speed and the target engine torque of the internal combustion engine in consideration of the whole system efficiency and a target engine power. 
     
     
       6. The drive control apparatus according to  claim 5 , further comprising a target engine power calculator configured to calculate the target engine power from a target drive power and a target charge-discharge power. 
     
     
       7. The drive control apparatus according to  claim 6 , further comprising a target drive power calculator configured to set the target drive power based on an accelerator opening and a vehicle speed. 
     
     
       8. The drive control apparatus according to  claim 6 , further comprising a target charge-discharge power calculator configured to calculate the target charge-discharge power based on a state of charge of a battery. 
     
     
       9. The drive control apparatus according to  claim 7 , further comprising an accelerator opening detector configured to detect the accelerator opening. 
     
     
       10. The drive control apparatus according to  claim 7 , further comprising a vehicle speed detector configured to detect the vehicle speed. 
     
     
       11. The drive control apparatus according to  claim 8 , further comprising a battery charge state detector configured to detect the state of charge of the battery. 
     
     
       12. A drive control method for a hybrid vehicle using outputs from an internal combustion engine and a motor generator, the drive control method comprising:
 determining a target engine torque of the internal combustion engine in consideration of the entire system efficiency and a target engine power; 
 comparing a torque command value of the motor generator to a permissible output torque of the motor generator; and 
 decreasing the target engine torque of the internal combustion engine when an absolute value of the permissible output torque of the motor generator is smaller than an absolute value of the torque command value of the motor generator. 
 
     
     
       13. The drive control method according to  claim 12 , further comprising setting a minimum engine torque to the target engine torque, and keeping the target engine torque from falling below the minimum engine torque when the target engine torque is decreased. 
     
     
       14. A hybrid vehicle comprising:
 a target engine torque setter configured to set a target engine torque of the internal combustion engine; 
 a motor torque command value calculator configured to set a torque command value of the motor generator; and 
 an engine torque corrector configured to make a correction of the target engine torque by a target engine torque correction value which is set based on a permissible output torque of the motor generator and the torque command value of the motor generator, 
 wherein the engine torque corrector is configured to make the correction by decreasing the target engine torque when an absolute value of the permissible output torque of the motor generator is smaller than an absolute value of the torque command value of the motor generator. 
 
     
     
       15. In a hybrid vehicle:
 a first planetary gear set including a first sun gear, a first ring gear, and a first planetary carrier which supports first planetary gears meshed with the first sun gear and the first ring gear; 
 a second planetary gear set including a second sun gear, a second ring gear, and a second planetary carrier which supports second planetary gears meshed with the second sun gear and the second ring gear, 
 the second sun gear being connected to the first planetary carrier, the second planetary carrier being connected to the first ring gear; 
 a drive control apparatus providing a target engine torque, a first torque command value and a second torque command value; 
 a first motor generator connected to the first sun gear, the first motor generator being operable on the first torque command value; 
 an internal combustion engine connected to the second sun gear, the internal combustion engine being operable on the target engine torque; 
 an output section connected to the first ring gear; and 
 a second motor generator connected to the second ring gear, the second motor generator being operable on the second torque command value, 
 the drive control apparatus configured to: 
 (a) determine a permissible output torque of the first motor generator; 
 (b) compare the first torque command value to the permissible output torque; and 
 (c) decrease the target engine torque when an absolute value of the permissible output torque is smaller than an absolute value of the first torque command value.